The present invention relates to dental devices, and more particularly to gingival retraction cords.
In dental treatment, it is often necessary to retract gingival tissue from a tooth in order to prepare the patient for taking impressions, setting crowns, or effecting restorations. Typically, the retractions are made using gingival retraction cords fabricated of cotton and impregnated with a therapeutic preparation.
One known method of effecting a gingival retraction is illustrated in FIG. 1 of the drawings, wherein tooth 110 is shown prepared for the installation of a crown and includes roots 112 and 114 extending into gingival tissue 116. Gingival crevice 118 is located between tooth 110 and gingival tissue 116 and is retracted from tooth 110 by packing cords 120 into crevice 118. Suitable cords include those manufactured by Pascal Company, Incorporated of Bellevue, Wash., under the trademark PASCORD, SUPER PAK, RACORD, and HEMAL-PAK. Generally, retraction cord is sold in bulk in three standard sizes or diameters, specifically No. 8, No. 9, and No. 10. In retracting gingival tissue 116, gingival crevice 118 preferably flares outwardly from bottom 118a to top to facilitate the taking of impressions and moldings thereabout. Therefore, a first length of No. 8 small diameter retraction cord 122 is unspooled from a bulk container, cut to the appropriate length, and packed about tooth 110 in gingival crevice 118. Second, a length of No. 9 or medium diameter cord 124 is unspooled from the bulk container, cut to a predetermined length, and packed in gingival crevice 118 on top of small diameter cord 122. Finally, a length of No. 10 large diameter cord 126 is unspooled and cut from a third bulk container, and packed in gingival crevice 118 on top of medium diameter cord 124. After a period of time, approximately five minutes, the cords are removed and the impression material is injected around the tooth 110, and particularly into gingival crevice 118, to complete the molding operation. Known flexible retraction apparatuses used are illustrated in U.S. Pat. No. 4,321,038, entitled BRAIDED GINGIVAL RETRACTION CORD and issued Mar. 23, 1982, to Porteous (braided cotton cord); and U.S. Pat. No. 3,238,620, entitled METHOD OF PREPARING AN IMPRESSION OF A TOOTH and issued Mar. 8, 1966, to Robertson (leather ring).
However, known gingival retraction materials and methods are not without their drawbacks. First, known cords are typically sold in bulk, spooled within a dispensing container. Consequently, removing the cord from the containers and judging and cutting appropriate lengths are time-consuming and laborious. The cord often becomes entangled with itself within the container making removal difficult or even impossible. Second, two or three separate cords are often required to effect the tissue retraction, further creating inconvenience and delays.